Balloon Catheter Assisted by Pulling a Puller-Wire

ABSTRACT

A medical instrument includes a shaft, a distal-end assembly and a puller-wire. The shaft is configured for insertion into a body of a patient. The distal-end assembly, which is coupled to the shaft, includes a telescopic assembly, configured to elongate so as to collapse the distal-end assembly, and to compress so as to expand the distal-end assembly. The distal-end assembly further includes an elastic element, coupled to self-elongate and thus elongate the telescopic assembly. The distal-end assembly also includes an inflatable balloon, which is coupled to the telescopic assembly and is configured to collapse by the telescopic assembly elongating, and to expand by the telescopic assembly compressing. The puller-wire runs through the shaft and is connected to a distal end of the telescopic assembly, and is configured, when pulled, to compress the telescopic assembly.

FIELD OF THE INVENTION

The present invention relates generally to medical probes, andparticularly to design and manufacturing of balloon catheters.

BACKGROUND OF THE INVENTION

Various catheters employ different kinds of mechanisms for maneuveringthe catheter distal end. For example, U.S. Patent ApplicationPublication 2004/0092868 describes a catheter to be used without aguidewire. The catheter includes a support wire shaft formed of metal, aballoon mounted on a distal portion of the catheter, and an inflationshaft for inflating the balloon, wherein a core wire may beinterchangeably inserted into the support wire shaft when the catheteris within a human body to change the stiffness and improve controlthereof.

As another example, U.S. Patent Application Publication 2005/0038506describes a medical device for treating a defective heart valve. Themedical device comprises a distal anchoring member for disposing in ablood vessel, a proximal anchoring member for disposing in or at anentrance of the blood vessel, and a telescoping assembly coupling at afirst end to the distal anchoring member and at a second end to theproximal anchoring member. The telescoping assembly is deployable intothe blood vessel. The telescoping assembly reduces a distance betweenthe distal anchoring member and the proximal anchoring member, whereinthe telescoping assembly comprises of at least two members capable ofsliding into each other giving the telescoping assembly adjustablelengths.

U.S. Pat. No. 6,780,183 describes a circumferential ablation catheterhaving a moveable tube that extends through a lumen of an inner supportmember and through the catheter body. The moveable tube islongitudinally moveable relative to the inner support member andcatheter body and has a distal end that extends beyond the distal end ofthe inner support member. An inflatable balloon is provided generally insurrounding relation to the circumferential ablation element. Theinflatable balloon has a proximal end attached, directly or indirectly,to the distal end of the catheter body and a distal end attached,directly or indirectly, to a portion of the moveable tube that extendsbeyond the distal end of the inner support member. Longitudinal movementof the moveable tube relative to the catheter body and inner supportmember causes movement of the distal end of the balloon relative to theproximal end of the balloon to thereby change the length and shape ofthe expanded balloon. First and second off centered puller-wires areprovided for deflection of the catheter body.

U.S. Pat. No. 5,383,923 describes a steerable catheter, which is adaptedto be inserted into a body lumen. The catheter comprises a symmetricalcylindrical control handle, an elongate tubular catheter body, and aflexible catheter tip having a lumen offset from the axis of thecatheter tip. The control handle comprises a housing having a pistonchamber at its distal end. A piston is mounted in the piston chamber andis afforded lengthwise movement. The proximal end of the catheter bodyis fixedly attached to the distal end of the piston. A puller-wire madeof nickel-titanium alloy having shape memory is attached to the housingand extends through the piston, through and coaxial with the catheterbody and into the offset lumen of the catheter tip where it is attachedto the wall of the catheter tip. Lengthwise movement of the pistonrelative to the housing results in deflection of the catheter tip.

U.S. Pat. No. 7,931,616 describes a deflectable catheter whose pullermember connections are accomplished with minimal, if any, surfacedeformation which could otherwise accelerate breakage under tension. Thecatheter includes a molded member that encases an end of a puller memberto enable connection of the end to a fixed or movable structure in thecontrol handle without significant surface deformation in the pullermember. The molded member is of a thermoplastic material that encases apreformed end of the puller member, which may be a puller-wire or a highmodulus fiber material. The molded member may be configured as desired,for example, as a screw that is fastened to a structure in the controlhandle. Alternatively, the preformed end of the puller member, forexample, a puller-wire, can be directly connected to and jointly encasedin the molded member with another preformed end of a second pullermember, for example, a high modulus fiber material. Such a connectedpuller member whose distal portion is the puller-wire and whose proximalportion is the high modulus fiber material can be well suited forcontrol handle that employs pulleys for increased throw capacity.

SUMMARY OF THE INVENTION

An embodiment of the present invention provides a medical instrumentincluding a shaft, a distal-end assembly and a puller-wire. The shaft isconfigured for insertion into a body of a patient. The distal-endassembly, which is coupled to the shaft, includes a telescopic assembly,configured to elongate so as to collapse the distal-end assembly, and tocompress so as to expand the distal-end assembly. The distal-endassembly further includes an elastic element, coupled to self-elongateand thus elongate the telescopic assembly. The distal-end assembly alsoincludes an inflatable balloon, which is coupled to the telescopicassembly and is configured to collapse by the telescopic assemblyelongating, and to expand by the telescopic assembly compressing. Thepuller-wire runs through the shaft and is connected to a distal end ofthe telescopic assembly, and is configured, when pulled, to compress thetelescopic assembly.

In some embodiments, the inflatable balloon includes a distal endconnected to a distal section of the telescopic assembly, and a proximalend connected to a proximal section of the telescopic assembly. In someembodiments, the elastic element includes one or more springs. In anembodiment, the elastic element includes one or more elastic splines. Inanother embodiment, the medical instrument further includes a handle,which is located outside the body and is configured to pull thepuller-wire.

There is additionally provided, in accordance with an embodiment of thepresent invention, a method, including inserting into a body of apatient a medical instrument, which includes a distal-end assemblycoupled to a shaft. The distal-end assembly includes (i) a telescopicassembly configured to elongate so as to collapse the distal-endassembly, and to compress so as to expand the distal-end assembly, (ii)an elastic element coupled to self-elongate and thus elongate thetelescopic assembly and (iii) an inflatable balloon, which is coupled tothe telescopic assembly and is configured to collapse by the telescopicassembly elongating, and to expand by the telescopic assemblycompressing. The method further includes compressing the telescopicassembly by pulling a puller-wire, which runs through the shaft and isconnected to a distal end of the telescopic assembly.

There is also provided, in accordance with an embodiment of the presentinvention, a method, including fitting at a distal end of a shaft adistal-end assembly, which includes a telescopic assembly, configured toelongate so as to collapse the distal-end assembly, and to compress soas to expand the distal-end assembly, an elastic element, coupled toself-elongate and thus elongate the telescopic assembly, and wherein thedistal-end assembly further includes an inflatable balloon, which iscoupled to the telescopic assembly and is configured to collapse by thetelescopic assembly elongating, and to expand by the telescopic assemblycompressing. The method further includes running a puller-wire throughthe shaft and connecting the puller-wire to a distal end of thetelescopic assembly such that pulling the puller-wire compresses thetelescopic assembly.

The present invention will be more fully understood from the followingdetailed description of the embodiments thereof, taken together with thedrawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic, pictorial illustration of a ballooncatheterization system comprising a telescopic balloon assembly, inaccordance with an embodiment of the present invention;

FIGS. 2A and 2B are schematic, pictorial illustrations of a telescopicballoon assembly in telescopically elongated and compressed states, inaccordance with an embodiment of the present invention;

FIGS. 3A and 3B are schematic, pictorial illustrations of a telescopicballoon assembly in telescopically elongated and compressed states, inaccordance with another embodiment of the present invention; and

FIG. 4 is a flow-chart that schematically illustrates a method fortelescopically compressing and elongating a telescopic balloon assemblyusing a puller-wire and an elastic element, respectively, in accordancewith an embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS Overview

Embodiments of the present invention that are described hereinafterprovide improved methods and mechanisms for expanding and collapsing aballoon at a distal end of a medical instrument, e.g., a cardiacablation catheter. In some embodiments, the medical instrument comprisesa telescopic assembly fitted at a distal end of a shaft, an elasticelement coupled to retain the telescopic assembly in an elongated state,a puller-wire connected to compress the telescopic assembly undercontrol of a physician. An inflatable balloon is coupled to be retainedin an elongated, collapsed state by the telescopic assembly being in anelongated state, and to be prepared for inflation and expand due to thetelescopic assembly being compressed.

The puller-wire may be thin and highly flexible (e.g., as there is noneed for the wire to be stiff as for example pusher-wires need to). Thepuller-wire is connected to the telescopic assembly such that pullingthe puller-wire compresses the telescopic assembly. The elastic element,such as a spring, is coupled to the telescopic assembly such that whenit self-elongates it elongates the telescopic assembly. In someembodiments, an inflatable balloon is coupled to the telescopic assemblysuch that the compression of the telescopic assembly facilitates theinflation of the balloon, while elongating the telescopic assemblyassists collapsing the balloon.

The compression and extension of the telescopic assembly may be realizedby causing one or more sections of the telescopic assembly totelescopically slide into one another. Various realizations andvariations of a telescopic motion that compresses the telescopicassembly by pulling a puller-wire, and elongating the telescopicassembly by a self-elongating elastic element applying an opposingforce, are possible.

As an example, the telescopic assembly may by compressed by pulingproximally a distal section, or by pulling distally a proximal section,or by a combination thereof, depending on detailed alternative designsof elements such as transmission mechanisms of the puller-wire andarrangements of one or more opposing elastic elements. Hence,embodiments that are provided hereinafter serve to exemplify severalpossible realizations, whereas potentially many more may occur topersons skilled in the art.

In various embodiment, any relevant implementation of (a) a telescopicassembly (b) an elastic element, and (c) a puller-wire, which togetherenable the elongation and compression of the telescopic assembly asdescribes herein. It is therefore to be understood that certainmechanical parts and/or principles may be included or omitted inpossible realizations, and that the principles provided by the disclosedembodiments can be implemented using numerous other possiblerealizations.

In some embodiments, the telescopic assembly includes a movable distalsection and a proximal section fixed to a shaft. The telescopic motionbetween the distal section and the fixed proximal section eithercompresses or elongates the overall length of the two-section telescopicassembly.

In some embodiments an inflated balloon is coupled to the telescopicassembly. A distal end of the inflated balloon is coupled to the distalend of the distal section, while a proximal end of the balloon iscoupled to the proximal end of the proximal section. With thisconfiguration, motion of the distal section in the distal direction,which elongates the telescopic assembly, elongates the balloon so as toassist its collapsing by evacuating the saline from the interior of theballoon. By the same token, motion of the distal section in the proximaldirection, which compresses the telescopic assembly, contracts theballoon in a longitudinal direction (i.e., parallel to the telescopicmotion) and by doing so allows the balloon to be inflated.

In some embodiments, the elastic element retains the telescopic assemblyin a normally-elongated state. A puller-wire running through the shaftis connected to the distal section. When the puller-wire is pulled inthe proximal direction by the physician, the puller-wire pulls thedistal section proximally so as to compress the telescopic assembly. Thecompression of the telescopic assembly contracts the balloon from itselongated state and thus expands the balloon to make room for inflatingthe balloon (e.g., by filling the balloon with saline solution), inpreparation of performing some diagnostics and/or a therapy.

In some embodiments, the elastic element comprises one or moreself-elongating splines or springs, which elongate the telescopicassembly. In some embodiments, the one or more splines or springs arefixed at their proximal ends to the proximal section and are fixed attheir distal ends to the distal section. The splines or springs have apreformed shape that is an elongated one. As a result of their inducedinherent tendency to self-elongate, the splines or springs force thedistal section of the telescopic assembly to move distally so as toelongate the telescopic assembly to its maximal designed length. Inorder for the elongation to occur, the pulling force by which thepuller-wire is pulled or held should be weaker than the force that thesplines or springs exert on the distal section. The inflatable ballooncoupled to the telescopic assembly will be correspondingly elongated(and thus the telescopic assembly assists in bringing the balloon to acollapsed state).

Once the physician decides to retract the balloon assembly, he or shereleases some or all of the pulling tension in the puller-wire. Thesplines then self-elongate and push the distal section distally toassist the balloon in collapsing. When the balloon is collapsed andfully elongated, the physician can safely retract the balloon assemblyinto the catheter sheath and maneuver the catheter out of the patient'sbody.

When using the disclosed configurations, the puller-wire may be verythin and highly flexible. This feature is in contrast to solutions basedon pusher-wire, in which the pusher-wire must be rigid and thereforethick and less flexible. As such, the disclosed techniques, enablehighly flexible catheter designs capable of performing sharp turns. Ahighly flexible balloon catheter using the disclosed telescopic assemblyassisted by a puller-wire may thus particularly maneuverable via sharpdeflections of blood vessels, and by so overcoming an obstacle that mayotherwise hinder catheterization. Moreover, the overall catheterdiameter may be reduced.

System Description

FIG. 1 is a schematic, pictorial illustration of a ballooncatheterization system 20 comprising a telescopic balloon assembly 40,in accordance with an embodiment of the present invention. System 20comprises a catheter 21, wherein, as an inset 25 shows, a distal end ofshaft 22 of the catheter is inserted through a sheath 23 into a heart 26of a patient 28 lying on a table 29. The proximal end of catheter 21 isconnected to a control console 24. In the embodiment described herein,catheter 21 may be used for any suitable therapeutic and/or diagnosticpurposes, such as electrical sensing, balloon angioplasty and ablationof tissue in heart 26, to name just few possible medical usages ofinflatable balloon catheters.

Physician 30 navigates the distal end of shaft 22 to a target locationin heart 26 by manipulating shaft 22 using a manipulator 32 near theproximal end of the catheter and/or deflection from the sheath 23.During the insertion of shaft 22, telescopic balloon assembly 40 ismaintained in a collapsed configuration by sheath 23. By containingtelescopic balloon assembly 40 in an elongated (and thus collapsed)configuration, sheath 23 also serves to minimize vascular trauma alongthe way to target location.

Control console 24 comprises a processor 41, typically a general-purposecomputer, with suitable front end and interface circuits 38 forreceiving signals from catheter 21, as well as for applying treatmentvia catheter 21 in heart 26 and for controlling the other components ofsystem 20. Processor 41 typically comprises a general-purpose computer,which is programmed in software to carry out the functions describedherein. The software may be downloaded to the computer in electronicform, over a network, for example, or it may, alternatively oradditionally, be provided and/or stored on non-transitory tangiblemedia, such as magnetic, optical, or electronic memory.

The example configuration shown in FIG. 1 is chosen purely for the sakeof conceptual clarity. The disclosed techniques may similarly be appliedusing other system components and settings. For example, system 20 maycomprise other components and perform non-cardiac treatments.

Balloon Catheter Assisted by Pulling a Puller-Wire

FIGS. 2A and 2B are schematic, pictorial illustrations of telescopicballoon assembly 40 in elongated and compressed states, in accordancewith an embodiment of the present invention.

FIG. 2A show telescopic balloon assembly 40 in an elongated state fittedat the distal end of shaft 22. As seen, a proximal section 48 and adistal section 46 are assembled into a two-part structure of telescopicassembly 40. In some embodiments proximal section 48 and a distalsection 46 comprise a tube, but many other, non-cylindricalcross-sections, may be used. Proximal section 48 is coupled to shaft 22,while distal section 46 can move telescopically inside proximal section48, i.e., its motion is either proximally or distally along a directionparallel to shaft 22. As seen, balloon 44 is coupled at its distal endto distal section 46 by an anchor 56 and is coupled at its proximal endto proximal section 48 by an anchor 58.

The elongation of telescopic balloon assembly 40 is caused by splines 50self-elongating towards their pre-shaped lengths. As seen, inflatableballoon 44 is retained in an elongated state by telescopic assembly 40being in an elongated state.

A puller-wire 52 runs through shaft 22 and within the two-parttelescopic assembly and is connected to distal section 46 at a distaledge of section 46. In an embodiment, puller-wire 52 is operated (e.g.,pulled or relaxed) from a handle of catheter 21. When physician 30 isready to inflate balloon 44, the physician command compressingtelescopic balloon assembly 40, which is performed by pulling ofpuller-wire 52. As seen in FIG. 2B, the two-part telescopic assembly 40is compressed by pulling puller-wire 52 proximally forcefully enough fordistal section 46 to force one or more elastic splines 50 to bend. In anembodiment, a stopper 59 limits the motion of distal section 46 to therequired length. As seen in FIG. 2B, balloon 44 is longitudinallycontracted and so as to being ready to be inflated, for example, bypressurized saline solution.

When the physician command the elongation of telescopic balloon assembly40, the force at which puller-wire 52 is pulled proximally is reducedsufficiently by a pulling apparatus (not described) to let splines 50 toself-elongate. Correspondingly, inflatable balloon 44 is elongated,making the balloon ready for retraction into sheath 23.

The example illustrations shown in FIGS. 2A and 2B are chosen purely forthe sake of conceptual clarity. Elastic splines 50 may have differentshapes and may be made from various materials. Other telescopicarrangements are possible. For example, distal section 46 may encompassproximal section 48 from the outside. As another example, the telescopicassembly may comprise more than two sections. Stopper 59 is brought byway of example only, the limit over distal section 46 motion may berealized, among other options, electronically, by using for example, aproximity sensor. As another example, the limit over of the motion ofdistal section 46 can be realized by setting the pulling force(transmitted by puller-wire 52) such it is balanced by the resistanceelastic splines 50 at a given bend of splines 50, which brings thetelescopic assembly into static equilibrium at a given pre-designedlength.

FIGS. 3A and 3B are schematic, pictorial illustrations of telescopicballoon assembly 40 in elongated and compressed states, in accordancewith another embodiment of the present invention.

In the embodiment exemplified by FIGS. 3A and 3B, a spiral (helical)spring 51, which is enclosed in proximal section 48 and pressed againstdistal section 46, is used for pushing distal section 46 to elongatetelescopic balloon assembly 40. As seen in FIG. 3B, pulling puller-wire52 compresses telescopic balloon assembly 40 and by so longitudinallycontracts balloon 44 to enable the inflation of balloon 44. The exampleillustration shown in FIGS. 3A and 3B is brought mainly to demonstratethat various designs are possible for achieving the same end resultelaborated above of compressing and elongating telescopic balloonassembly 40. Additional designs with vast options for of elements andmaterials may occur to persons skill in the art.

FIG. 4 is a flow-chart that schematically illustrates a method fortelescopically compressing and elongating telescopic balloon assembly 40using puller-wire 52, in accordance with an embodiment of the presentinvention.

The process may begin with physician 30 advancing telescopic balloonassembly 40 while being held collapsed in sheath 23, at a balloonadvancement step 70. Physician 30 may advance sheath 23 through sharpdeflections of blood vessels, as such pose less of an obstacle to thehighly flexible shaft 22 of catheter 21 (a flexibility attributedlargely to the high flexibility of puller-wire 52 within shaft 22).

After physician 30 navigated telescopic balloon assembly 40 to itstarget location in heart 26, physician 30 retracts sheath 23 or advancesballoon assembly 40, exposing the elongated telescopic balloon assembly40. Physician 30 then commands the pulling of puller-wire 52, so as totelescopically compress telescopic balloon assembly 40 and by solongitudinally contracting balloon 44 to enable inflating balloon 44, ata pulling step 72. Physician 30 inflates balloon 44, at an inflationstep 74, and performs the required clinical procedure, at a clinicalstep 76.

Once physician 30 wishes to deflate balloon 44, physician 30 commandsthen a relaxation of tension which puller-wire 52 transmits, allowingsplines 50 to self-elongate so as to telescopically elongate telescopicballoon assembly 40 and correspondingly elongate balloon 44, at anelongation step 78. The elongation of balloon 44 assists deflating andcollapsing balloon 44. The physician can then safely retract theelongated and collapsed telescopic balloon assembly 40 back into sheath23, in retraction step 80.

The example flow chart shown in FIG. 4 is chosen purely for the sake ofconceptual clarity. The operation method of telescopic balloon assembly40 is to serve only as an illustrative example of a puller-wire methoddisclosed. For example, physician 30 may perform additional steps prior,during or after clinical step 74.

Although the embodiments described herein mainly address cardiacapplications, the methods and systems described herein can also be usedin other applications, such as otolaryngology or neurology procedures.

It will thus be appreciated that the embodiments described above arecited by way of example, and that the present invention is not limitedto what has been particularly shown and described hereinabove. Rather,the scope of the present invention includes both combinations andsub-combinations of the various features described hereinabove, as wellas variations and modifications thereof which would occur to personsskilled in the art upon reading the foregoing description and which arenot disclosed in the prior art. Documents incorporated by reference inthe present patent application are to be considered an integral part ofthe application except that to the extent any terms are defined in theseincorporated documents in a manner that conflicts with the definitionsmade explicitly or implicitly in the present specification, only thedefinitions in the present specification should be considered.

1. A medical instrument, comprising: a shaft for insertion into a bodyof a patient; a distal-end assembly, which is coupled to the shaft andcomprises: a telescopic assembly, configured to elongate so as tocollapse the distal-end assembly, and to compress so as to expand thedistal-end assembly; an elastic element, coupled to self-elongate andthus elongate the telescopic assembly; and an inflatable balloon, whichis coupled to the telescopic assembly and is configured to collapse bythe telescopic assembly elongating, and to expand by the telescopicassembly compressing; and a puller-wire, which runs through the shaftand is connected to a distal end of the telescopic assembly, and whichis configured, when pulled, to compress the telescopic assembly.
 2. Themedical instrument according to claim 1, wherein the inflatable ballooncomprises a distal end connected to a distal section of the telescopicassembly, and a proximal end connected to a proximal section of thetelescopic assembly.
 3. The medical instrument according to claim 1,wherein the elastic element comprises one or more springs.
 4. Themedical instrument according to claim 1, wherein the elastic elementcomprises one or more elastic splines.
 5. The medical instrumentaccording to claim 1, and comprising a handle, which is located outsidethe body and is configured to pull the puller-wire.
 6. A method,comprising: inserting into a body of a patient a medical instrument,which comprises a distal-end assembly coupled to a shaft, the distal-endassembly comprises (i) a telescopic assembly configured to elongate soas to collapse the distal-end assembly, and to compress so as to expandthe distal-end assembly, (ii) an elastic element coupled toself-elongate and thus elongate the telescopic assembly and (iii) aninflatable balloon, which is coupled to the telescopic assembly and isconfigured to collapse by the telescopic assembly elongating, and toexpand by the telescopic assembly compressing; and compressing thetelescopic assembly by pulling a puller-wire, which runs through theshaft and is connected to a distal end of the telescopic assembly. 7.The method according to claim 6, wherein the inflatable ballooncomprises a distal end connected to a distal section of the telescopicassembly, and a proximal end connected to a proximal section of thetelescopic assembly.
 8. The method according to claim 6, wherein theelastic element comprises one or more springs.
 9. The method accordingto claim 6, wherein the elastic element comprises one or more elasticsplines.
 10. The method according to claim 6, wherein compressing thetelescopic assembly comprises pulling the puller-wire by a handlelocated outside the body.
 11. A method, comprising: fitting at a distalend of a shaft a distal-end assembly, which comprises: a telescopicassembly, configured to elongate so as to collapse the distal-endassembly, and to compress so as to expand the distal-end assembly; anelastic element, coupled to self-elongate and thus elongate thetelescopic assembly; and an inflatable balloon, which is coupled to thetelescopic assembly and is configured to collapse by the telescopicassembly elongating, and to expand by the telescopic assemblycompressing; and running a puller-wire through the shaft and connectingthe puller-wire to a distal end of the telescopic assembly such thatpulling the puller-wire compresses the telescopic assembly.